From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AFC984BF959 for ; Wed, 30 Sep 2026 19:36:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790797010; cv=none; b=tM5RmBMwpJX0TpyF/1uIaA41Qnh0vKDZ3wXu0l12l1Zvglk+j/7LuqFY/mswN9LyIvfwcIHi+/NNXRV9oKpwYAzXZE0pzvt694TePuq6vZi1aufmt14+9mjQMSlIDCbffS11+bIdwrlOi6Sz983cliQhmnruBp3+/7IjmLboQHs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790797010; c=relaxed/simple; bh=qNaxT1lfEbT1LPSsEVh5+AezcCglRx9kPOdT2poCI4Y=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Y0tpDdiKJUNl2VTt6Fmgmd1GWDavB4Ipea6utvRK1+K3mn16bZoHlCzRxNO2dxcBpw20O87gLbX0hzxhvFW5NP/abBa1oqpHLG9yh4CZeJUJ4twvX3207Mwzh22B/bn9+S/1jFAFbIHFvelkPAHVbaaZ1VWPky7D9bUc0zy8Dg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=VUBsoK46; arc=none smtp.client-ip=209.85.215.198 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="VUBsoK46" Received: by mail-pg1-f198.google.com with SMTP id 41be03b00d2f7-cc72777faa2so3337008a12.1 for ; Wed, 30 Sep 2026 12:36:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790797008; x=1791401808; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=vlcl2f6ewwzrBjcQFC4aq+Z9uRrmySkT+V2ro3tMTk0=; b=VUBsoK46WEyZTpYVlR8l0P+kUd03RmBT/YMOzz8Tj8MUsluuwoZfvQHy+pq8PwadMn 6i+NdC+SVUWOsaFtP5sDpdBkmpzw6Mz2iYtii6EVRqUypOCnsP2pEHtMSWo9c/Bqi6/H kUvBKupaND7/MkKgUf67nfxwqgyO3xfDY+wddWoHHh2JVTiRMG1HkkxS7FR0qqxn3Cff CNHMUdHaYqcx1BDSr7Iz66cED9E1w+GHjoR47GoRK5BM319xMNHF6WQjNzT1ZQbsmX2r SjEe4MBK7ZS3yiyIWvBjwWxTAIbb/Guft+1LeYwuJG1v1L1VR6z+e/ixywpNoL7stM9N lTMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790797008; x=1791401808; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=vlcl2f6ewwzrBjcQFC4aq+Z9uRrmySkT+V2ro3tMTk0=; b=Ikv5iOKVkQC1Hrnhkwf9iDLjFNyidjfnT5aeQoCv+uQuEPe6wv6aqSJQTAF1HauhrJ 4gPr9PA6mqBXiKimt7hnC7pp1zAjv+Lt9X3pghh54aLr+viRwRu0ldSdGDYoBDI+nJdh p8gPBvCnaDWLQ6ScBbQ3is+M1SIVlItaKDbSoMmFTIU/M+DuuNYdBV2md3rHb41jhoEI o9ntsqxKWyW6cUzsXaFiOlXq1Xp9pPKnNpX3g95PhDSg8f55lVIle3g+wVTq4u1rmumR HE2mBsVxvPmjeKbboKyQ4Zta2mA3QDz58f9dljSrLMxC+2B+N96Rso2vbqDRI/T3Qi6Z T4Cg== X-Forwarded-Encrypted: i=1; AKwUvBwkdq6CgQY3rwYWfWaVObh4A8qeYVQEM8fxRs5NNZXqxWNHPd5iyJt2iGibVApe+JsY/P7aFg3iQ+L4Ef0=@vger.kernel.org X-Gm-Message-State: AFuF++lSuFr/JBn9bXuzsoLK5/L9+CVbiNias5cD+nw4dhlhoqv3oWr3 fvSsDI3eVLW/0D0+K92XUHLzR+EeQmdw5ykFhaFCmOlv0RUEy5ItZ6GjoXRKnz5U1nPCp5uTN6g naYn+wA== X-Received: from pgbdo4.prod.google.com ([2002:a05:6a02:e84:b0:cc7:d747:ae32]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:2d4b:b0:3de:53ba:4071 with SMTP id adf61e73a8af0-3de9e740039mr2189302637.32.1790797007784; Wed, 30 Sep 2026 12:36:47 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 30 Sep 2026 12:36:30 -0700 In-Reply-To: <20260930193634.3415089-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260930193634.3415089-1-seanjc@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20260930193634.3415089-9-seanjc@google.com> Subject: [PATCH v6 08/12] KVM: nSVM: Disable LBRV in nested control cache when unsupported From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , Shivansh Dhiman , Nikunj A Dadhania , Ravi Bangoria , Tom Lendacky Content-Type: text/plain; charset="UTF-8" From: Shivansh Dhiman Clear SVM_MISC2_ENABLE_V_LBR in __nested_copy_vmcb_control_to_cache() when the vCPU does not support LBR Virtualization. This lets the cached value be consumed directly instead of re-checking X86_FEATURE_LBRV on every access. Suggested-by: Yosry Ahmed Signed-off-by: Shivansh Dhiman Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/nested.c | 8 +++++--- arch/x86/kvm/svm/svm.c | 2 +- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index b61149814acc..aca2bbc66f47 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -527,12 +527,16 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu, /* Always clear misc_ctl bits that the guest cannot use */ to->misc_ctl = from->misc_ctl; + to->misc_ctl2 = from->misc_ctl2; if (!guest_cpu_cap_has(vcpu, X86_FEATURE_NPT)) to->misc_ctl &= ~SVM_MISC_ENABLE_NP; if (!gmet_enabled || !guest_cpu_cap_has(vcpu, X86_FEATURE_GMET)) to->misc_ctl &= ~SVM_MISC_ENABLE_GMET; + if (!guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV)) + to->misc_ctl2 &= ~SVM_MISC2_ENABLE_V_LBR; + to->iopm_base_pa = from->iopm_base_pa & PAGE_MASK; to->msrpm_base_pa = from->msrpm_base_pa & PAGE_MASK; to->tsc_offset = from->tsc_offset; @@ -550,7 +554,6 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu, to->event_inj_err = from->event_inj_err; to->next_rip = from->next_rip; to->nested_cr3 = from->nested_cr3; - to->misc_ctl2 = from->misc_ctl2; to->pause_filter_count = from->pause_filter_count; to->pause_filter_thresh = from->pause_filter_thresh; @@ -737,8 +740,7 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, static bool nested_vmcb12_has_lbrv(struct kvm_vcpu *vcpu) { - return guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && - (to_svm(vcpu)->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR); + return to_svm(vcpu)->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR; } static void nested_vmcb02_prepare_save(struct vcpu_svm *svm) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 775eccfb7b24..5253c0143666 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -882,7 +882,7 @@ static bool svm_need_lbr_virtualization(struct kvm_vcpu *vcpu) if (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) return true; - return is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && + return is_guest_mode(vcpu) && (svm->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR); } -- 2.56.0.rc1.315.gc6ed9934b7-goog